1. Field
The present disclosure relates to a polymeric compound, an oxygen permeable membrane, an oxygen permeable composite, and an electrochemical device. More particularly, the present disclosure relates to a polymeric compound, which selectively intercalates or deintercalates oxygen, an oxygen permeable membrane including the polymeric compound, an oxygen permeable composite including the oxygen permeable membrane, and an electrochemical device including the oxygen permeable membrane.
2. Description of the Related Art
Recently, certain electrochemical devices, such as rechargeable secondary batteries using oxygen as a positive active material, such as lithium air cells, have drawn close attention. In such electrochemical devices, oxygen is externally supplied (from the air or an external oxygen supply unit) during a discharging operation, to take part in oxidation-reduction reactions in electrodes during charging and discharging. Thus, in electrochemical devices, such as lithium air batteries, in which bases its function on a redox reaction of oxygen, rapid injection of oxygen into the device significantly improves its electrical capacity. Because oxygen in the air is present in the mixture with other gaseous components, for example, nitrogen, a selective and efficient method of injection of the oxygen into the electrochemical device is desirable. To address this problem, a part of the electrochemical device capable of selectively binding (by way of intercalation/deintercalation) to oxygen molecules may be disposed in an oxygen inlet near a positive electrode (air electrode) of an electrochemical device.
One material capable of selectively binding to oxygen, is a cobalt porphyrin complex (hereinafter, referred to as a “CP” complex). Since a membrane, including the CP complex, is selectively permeable to oxygen gas, such a membrane has been suggested for and found utility in industrial use as an oxygen-selective permeable membrane or an oxygen enrichment membrane.
However, the CP complex is a rigid molecule which displays little flexibility. Accordingly, to improve the physical properties of the membrane, a portion of a polymer backbone unit excluding the CP complex, or a portion of a polymer material mixed with the CP complex, needs to be increased. However, this increase may prevent the CP complex ability from selectively intercalating and deintercalating oxygen, and may prevent an oxygen permeability of a CP complex-based membrane from being fully exhibited. Thus, there remains a need to produce a membrane possessing satisfactory oxygen permeability.